734 research outputs found
Income and Health in Tanzania. An Instrumental Variable Approach
SummaryThere is a substantial debate over the direction of the causal relation between income and health. This is important for our understanding of the health production process and for the policy debate over improving healthcare. We instrument income with rainfall measurements by matching satellite information on timing and positioning of 21 rainfall stations to longitudinal data (1991–94) of over 4,000 individuals in 51 villages in Tanzania. A 10% increase in income reduces the number of illnesses by 0.02. We also find that a 10% increase in income implies an increase of about 0.1 vaccinations of children under six
Twin reversed arterial perfusion sequence: current treatment options
Twin reversed arterial perfusion (TRAP) sequence is a specific and severe complication of monochorionic multiple pregnancy, characterized by vascular anastomosis and partial or complete lack of cardiac development in one twin. Despite its rarity, interest in the international literature is rising, and we aimed to review its pathogenesis, prenatal diagnostic features and treatment options. Due to the parasitic hemodynamic dependence of the acardiac twin on the pump twin, the management of these pregnancies aims to maximize the pump twin’s chances of survival. If treatment is needed, the best timing of intervention is still debated, although the latest studies encourage intervention in the first trimester of pregnancy. As for the technique of choice to interrupt the vascular supply to the acardiac twin, ultrasound-guided laser coagulation and radiofrequency ablation of the intrafetal vessels are usually the preferred approaches
Experimental Nonlinear Control for Flutter Suppression in a Nonlinear Aeroelastic System
Experimental implementation of input–output feedback linearization in controlling the dynamics of a nonlinear pitch–plunge aeroelastic system is presented. The control objective is to linearize the system dynamics and assign the poles of the pitch mode of the resulting linear system. The implementation 1) addresses experimentally the general case where feedback linearization-based control is applied using as the output a degree of freedom other than that where the physical nonlinearity is located, using a single trailing-edge control surface, to stabilize the entire system; 2) includes the unsteady effects of the airfoil’s aerodynamic behavior; 3) includes the embedding of a tuned numerical model of the aeroelastic system into the control scheme in real time; and 4) uses pole placement as the linear control objective, providing the user with flexibility in determining the nature of the controlled response. When implemented experimentally, the controller is capable of not only delaying the onset of limit-cycle oscillation but also successfully eliminating a previously established limit-cycle oscillation. The assignment of higher levels of damping results in notable reductions in limit-cycle oscillation decay times in the closed-loop response, indicating good controllability of the aeroelastic system and effectiveness of the pole-placement objective. The closed-loop response is further improved by incorporating adaptation so that assumed system parameters are updated with time. The use of an optimum adaptation parameter results in reduced response decay times
Hepatocellular carcinoma in pregnancy: A systematic review
Introduction: Hepatocellular carcinoma (HCC) is the most frequent primary malignant liver tumor and typically develops in the context of chronic liver disease, such as liver cirrhosis or chronic hepatitis B virus infection. Ultrasound evaluation, CT scan, and MRI are used to detect HCC. α-fetoprotein (AFP) is a common marker used to detect HCC in the non-pregnant population, which notoriously increases in pregnant women in relation to gestational age. Treatment is driven by the extent of the disease and the severity of underlying liver disease. Pregnancy may represent an obstacle to diagnosis and appropriate treatment of HCC. The aim of this descriptive systematic review was to describe the clinical features and maternal and neonatal outcomes of HCC in pregnancy. Material and methods: We performed a systematic review of the literature about HCC diagnosed in pregnancy and the postpartum period, with signs or symptoms arising in pregnancy. We included case reports and case series describing the clinical features of women diagnosed with HCC, fibrolamellar variant of HCC, and mixed HCC and cholangiocarcinoma during pregnancy or the postpartum period (with onset of symptoms during pregnancy), from inception to March 2023. The study protocol was registered with the PROSPERO database (Registration number: ID CRD42021275584). Results: We identified 180 records. The articles included in this systematic review were 47 case reports and 5 case series, for a total of 63 pregnancies. The two most frequent predisposing conditions were hepatitis B virus infection (30/63; 47%) and liver cirrhosis (14/63; 22%). Ultrasound evaluation was the most used technique to detect HCC. AFP was higher than normal in 28/46 patients tested (61%). Surgical treatment was the most used therapy, both during pregnancy and after delivery. Twenty-six patients (26/63; 42%) died within 6 months of diagnosis. Survival >24 months was 9% (4/46) in symptomatic and 29% (5/17) in asymptomatic women. No patient with cirrhotic liver survived more than 12 months. Thirty-eight newborns were alive at 28 days of age (38/63; 61%). Conclusions: Hepatocellular carcinoma in pregnancy is associated with a high risk of maternal and neonatal mortality. Diagnosis in asymptomatic high-risk women or following abnormal maternal serum AFP screening is associated with better maternal outcomes
High-Bandwidth Morphing Actuator for Aeroelastic Model Control
© 2019 by the authors. The design and testing of a high-bandwidth continuous actuator for aeronautical applications is presented hereinafter. The actuator has a dual goal of controlling both the aeroelastic behaviour and the flight mechanics of the model in which it is installed. In order to achieve these aims, the actuation bandwidth of the active aerofoil, as well as its static camber variation, have to be sufficiently high. The camber morph is achieved by using tailored piezoelectric patches in a sandwich configuration with a linear trailing edge slider to allow the necessary compliance. The morphing actuator is designed for a NACA 0018 aerofoil with a chord of 300mmand a span of 40 mm. Static and dynamic experimental tests are carried out on a prototype, and a camber variation control technique is implemented. It is proved that the actuator bandwidth is up to 25 Hz and the equivalent maximum deflection is ±15 degrees. This solution is shown to be a viable light-weight alternative to the conventional brushless/servo-motor approach currently used in aeroelastic models
MODEL REDUCTION AND STOCHASTIC UPDATING OF A VIBRATING SYSTEM
A two-level framework is demonstrated for stochastic model updating. At the first level, variance-based global sensitivity analysis is carried out with the purpose of identifying those parameters with significant uncertainty and those that might be considered deterministic and can be eliminated as inputs to the metamodel. Then, at the second level, an inverse problem is solved to determine the statistics of the parameters of a modification that causes numerical metamodel results to converge on experimental data. Model updating is carried on a second metamodel with only the significant parameters retained. The methodology makes use of the Woodbury formula, resulting in a set of nonlinear characteristic equations in the unknown terms. The framework methodology is applied to a simulated three degrees of freedom representation of an experimental rig. Complex-eigenvalue data is generated from known parameter distributions and bivariate output probability density functions are produced using kernel density estimation. By sampling from this data, estimates of the generating parameters and their distributions are recovered
Experimental Demonstration of a 5G Network Slice Deployment Through the 5G-Transformer Architecture
44th European Conference on Optical Communications (ECOC 2018)This demo shows for the first time the capability of the proposed 5G-TRANSFORMER architecture to deploy a 5G network slice in minutes. The slice consists of a mix of physical and virtual mobile network functions deployed in an Openstack environment.This work was supported by the EC through the Horizon 2020 5G-TRANSFORMER project (grant agreement 761536)
Influence of rainfall on E. coli concentrations in clams: results of collaboration between competent health authority and producers’ association in the Province of Fermo (Italy)
The Area Vasta di Fermo (the competent health authority of the Marche Region), in
collaboration with the local Producers’ Association conducted a series of studies on the
presence of E. coli as an indicator of faecal contamination in the environment, in shellfish and
in fishery waters, and on the factors that can affect their presence. These studies, carried out
from 2008 to 2011, included an assessment of the currents along the coast, of the
precipitations, and data from the monitoring of E. coli on shellfish harvested in the collection
areas were examined. The results showed that in most cases, small concentrations of
microorganisms in shellfish corresponded to little or no precipitations, while an increase in
the levels of E. coli was preceded by more or less abundant rainfalls.
The conclusions suggest that it is advisable to carry out a more detailed risk analysis
which should take into account the above-mentioned factors. Furthermore, monitoring alone
based on the determination of indicator organisms, especially when carried out as a single
analysis or with a small number of E. coli determinations, does not provide a satisfactory
indication of safety. The regional surveillance plans should be applied timely and rigorously,
together with on-site investigations aimed at identifying changes that can affect the presence
of E. coli in shellfish. Food business operators themselves could implement good
manufacturing practices to verify whether the microbiological parameters are within the
prescribed limits after rainfalls, especially if heavy
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